Method and apparatus for drawing and flattening sheet glass



Nov. 20 .1928.

E. T. FERNGREN METHOF'AND APPARATUS.

FOR RAWING AND FLATTENING SHEET GLASS Marph 31, 1,924

qa waimgiw INVENT UR Enoch Ifmgmn. N% ATT I] NEY.

Patented Nov. 20, 1928.

UNITED STATES 1,692,548 PATENT OFFICE.

ENOCl-I T. FERNGREN, OF TOLEDO, OHIO, ASSIGNOR- TO THE LIBBEY-OVENS SHEET GLASS COMPANY, OF TOLEDO, OHIO; A CORPORATION OF OHIO.

METHOD AND APPARATUS FOR DRA ING AND FLATTENING SHEET GLASS.

Application filed March 31, 1924. Serial No. 703,031.

This inventionrelates to the art of drawing sheet glass in continuous sheet form, and more particularly to an improved method and apparatus for continuously pulling the sheet from its molten source and simultaneously flatteningthe same.

It has been proposed heretofore to support the sheet during the flattening process upon a horizontal table composed of a series of parallel rollers, the rollers usually being driven to act as. a conveyor for the sheet.

7 Since the glass sheet must be drawn rather slowly and is still in a rather plastic condition, at least at the beginning of the flattening process, there is a tendency for the sheet to sag between the several lines of support furnished by the plurality of separate rollers.

According to the principles of this invention the series of supl'aorting rollers for the sheet are mounted in the form of an endless belt and moved bodily beneath the sheet, preferably in a direction opposite to that of the sheets travel, so as to more rapidly shift the .lines of support from one position to another beneath-the sheet, thus leaving no portion of the sheet unsupported for any material interval of time and giving it substantially no opportunity to sag. An endless drawing meansis mounted above the sheet, engaging the sheet at its edges and moving therewith at the same speed as the sheet. This drawing means acts not only to hold the sheet down on the supporting rollers, but also serves as a means for rotating each of the sheet-supporting rollers about its own axis at sucha speed that despite the bodily movement of the roller beneath the sheet it will have only rolling contact with the under-surface of the sheet.

The above and other objects and advantages of the invention will be more apparent from the following detailed description of certain approved forms of the apparatus.

In the accompanying drawings Fig. 1 is a side elevation, partly in longi tudinal vertical section, of the drawing and flattening mechanism and certain portions of the sheet-formingmechanism.

Fig. 2 is a transverse vertical section on an enlarged scale through one end of one of the supporting rollers, and the adjacent portions of the driving means and sheet-drawing mechanism.

Fig. 3 is a plan view of a portion of the drawing mechanism.

' belt-driving Fig. 4 is a fragment of the rotating mechanism for the-rollers.

Fig. 5 is asection through the combined and roller-cooling sprocket wheel. i

Fig. 6 shows a portion of a modified form of the apparatus.

In the sheet-forming mechanism here shown the glass sheet 1 is continuously drawn upward from the surface of the molten pool 9. 1n receptacle 3. The sheet passes up between coolers 4. and the small edge-drawing rollers 5, and is then bent, while still somewhat plastic, about the cooled bending roller 6 into the horizontal plane. This means of forming the sheet, which is substantially that disclosed in the Colburn patent-s, is merelyshown by way of example since the drawing and flattening mechanism about to be described could be used equally well in connection with any sheet-forming mechanism which delivers the plastic sheet into the horizontal plane. l The sheet supporting portion of the drawmg and flattening mechanism consists of a I series of parallel horizontal rollers 7. These rollers, which are comparatively small and mounted as closely adjacent one another as is practicable. are formed of some suitable heatresisting alloy such as nichrome, or Monel metal, capable of taking and retaining a highly polished surface, least apt to injure the firepolished surface of the glass sheet which will be carried thereby. Each roller 7 is hollow and in each end is secured a short hollow sleeve 8 having formed on its outer end a small gear 9 whose pitch diameter corresponds with the diameter of the sheet supporting surface of roller '7. Sleeve 8 and gear 9 are supported, preferably through roller bearings.

10, upon one end of a hollow sleeve 11 which forms one of the connecting pintles of the endless chain 12. Also mounted on pintle 11 is a flanged roller 13,also preferably supported on roller bearings, which travels upon an upper fixed horizontal track or guide 14 or a similar lower guide 15 both carried by the brackets 16 at the sides of the machine. By means of the rollers 13 travelling on the horizontal trackway. 14 the upper sheet-carrying portions of the peripheries of rollers 7 will always lie in thesame horizontal plane throughout the upper sheet-carrying run of the endless belt.

Mounted on a hollow vertical driving shaft 17 at the side of the machine is a rather large {)he guides 14 and 15 through an endless oreach end of the loop, so that the endless sheet-carrying belt can be driven in either.

direction as may be desired.

A passage 21 extends from the outer end ofeach tooth 19 of sprocket l8 to'the interior of hollow shaft 17. A fixed sleeve member 22 within the shaft 17 has an open slot 23 at one si'de which will always be opposite the passage 21 leading to the tooth then in engagement with one .of the chain pintles 11.

. Cooling air under pressure is forced through the teeth of the large sprockets 28 and hollow shaft 17 and will be blown out through the slot 23 and passage 21 through the tooth 19 and intle 11 .into the interior of one of the rollers% to cool the roller, and supporting chain members.

Mounted above the horizontal run 'of sheet 1 is a drawing mechanism comprising a pair of endless chains adapted to rest u on the edge portions of the sheet, and suita le connecting members whereby the two side chains move in unison. Each of these drawing chains comprises an inner chain of links 24 and an outer chain of similar links 25 having connecting pintles 26 carrying rollers 27 on:

their central portions between the side links 24 and 25. These rollers 27 are-enga ed by 29 at the ends of the loop which serve to support and drive the drawing mechanism. gear 30 meshes with the upper return run of the drawing chain and is so positioned as to prevent excessive slackin this run of the belt'an'd hold the belt positively in engagement withthe driving sprockets 28 and 29;

The outer row of links 25 are formed on their lower sides with teeth 31 which constitute, in the lower horizontal run of the drawing chain, a rack which meshes with and drives the ars 9 at the ends of, sheetmarrying rollers Extending from the inne'rsides of the inner' links 24 are plates 32 having teeth or rojections 33 adapted to bear down upon and grip the edge portions'of glass sheet 1. Transverse bars 34 bridge the u per-surface of glass sheet 1, out of contact therewith, and are secured at their ends to corresponding l plates 32. These bars serve to enforcean-even movement of the twodrawing chain sat the two sides of the sheet, and also add the necessary-weight tohold these chains positively in engagement with the upper surface of the sheet and with the driving gears 9 for the roller 7. I

Driving sprockets 28 will be driven at such Preferably there will be two of-these. drivlng sprockets 18, one positionednear desired speed to move the sheet-supporting roller-belt in either direction beneath the sheet surface. We will first assume that this belt is being moved in a clockwise direction, Fig. 1. beneath the sheet, that is so that the upper sheet-carrying run of the rollers is moving bodily in a direction opposite that in which sheet 1 is travelling. In this way the greatest relative movement between the sheet and roll ers is obtained. As each roller moves with relation to the drawing chain 25, the gear 9 at the end of the roller will roll along rack 31 on the lower surface of chain 25 and since the pitch-line in which gear 9 engages rack 31 lies in the same horizontal plane as the lower surface of glass sheet 1, the roller 7 will roll along the lower surface of the sheet, no matter at what speed or in which direction .it is moved. In this way there can be no sliding contact between the surface of roller 7 and glass sheet 1. The rollers 7 should be bodily moved at such a speed that no portion of glass sheet 1 will remain unsupported long enough to give it time to sag between the rollers. In other words, the lines of support formed bythe upper surfaces of the series of rollers are being shifted from place to place sov rapidly that practically a continuous support is provided for the lower surface of the sheet. At the same time this supporting surface has an entire rolling contact with the sheet, and there is no sliding engagement which might injure the fire-polished surface.

A series of burners indicated at 36, serve to maintain the chamber 37 beneath the sheetcarrying table at such. a temperature that the glass sheet will not be unduly chilled, or subjected to sudden local temperature changes asit passes on and off of the sheetcarrying rollers. The sheet-carrying surfaces of these rollers. should be maintained at -'a temperature substantially the same as that of the glass sheet .passing thereover. heatedatmosphere in chamber 37, passing up between the rollers 7, which are constantly shifting with relation to sheet 1, has a uniformly distributed heating efiect on the lower surface of the glass sheet, maintaining the glass sheet at the proper flattening tem- .arc of curvature than in the form previously The - .direction to the direction of travel of thedescribed, and glass sheet 1 is drawn upwardly from its molten pool and bent into the horizontal plane while supported upon this end loop of sheet-carrying rollers 7. In other words, the bending roller 6 previously described is omitted and the endless belt of rollers serves the double purpose of supporting the sheet during the bending operation and afterwards flattening it in the hori zontal plane. Otherwise this form of the mechanism operates the same as in the modification first described.

Claims:

1. In the art of continuously drawing sheet glass, the process of supporting the moving sheet during the flattening period along a plurality of straight parallel lines which are constantly shifting with respect to the sheet to prevent sagging of the sheet between the lineso't support.

2. In the art of continuously drawingsheet glass, the process of supporting the moving sheet during the flattening period, along a plurality of straight parallel lines which are constantly moving at a different speed than the sheet to change the supported portions of the sheet.

3. In the art of continuously sheet glass, the process of supporting the moving sheet during the flattening period along a plurality of straight parallel lines which are constantly moving in the opposite sheet to rapidly shift the lines of support and prevent sagging of the unsupported portions.

4. A drawing and flattening mechanism for continuously drawn sheet glass, comprising drawing means moving with the sheet, and bodily moving means supporting the sheet at a series of constantly shifting adjacent points.

5. A drawing and flattening mechanism for continuousiy drawn sheet glass, comprising drawing means moving with the sheet, and a series of rollers supporting the sheet and moving bodily therebeneath.

6. A drawing and flattening mechanism for continuously drawn sheet glass, comprising drawing means moving with the sheet, a series of rollers supporting the sheet, means for bodily moving the rollers beneath the sheet, and means for rotating the rollers about their own axes so that they have only rollingcontact with the sheet.

7. A drawing and flattening table for continuousl drawnsheet glass, comprising an endless elt havingan upper horizontal run on which the sheet is carried, the sheet-carrying portion of the belt consisting of a series of rollers. 7

8. -A drawing and flattening table for continuously drawn sheet glass, comprising an endless belt having an upper horizontal run on which the sheet is carried, the sheet-carrying portion of the belt consisting of a series an endless run on which the sheet is carried, the sheetdrawing of rollers, means for driving the belt, and

endless belt having an upper horizontal run on which the sheet is carried, the sheet-car rying portio'nof the belt consisting of a series of rollers, and means for driving the belt and simultaneously cooling the rollers.

10. A drawing and flattening table for continuously drawn sheet glass, comprising belt having an upper horizontal carrying portion of the belt consisting of a series of rollers, and a driving gear having teeth meshing with the ends of the rollers.

11. A drawing and flattening table for continuously drawn sheet glass,

an endless belt having an upper horizontal run on which the sheet is carried, the sheetbelt consisting of a carrying portion of the series of rollers, a driving gear having teeth meshing with the ends of the rollers, and means for delivering a cooling fluid through the gear teeth to the interior of the rollers in mesh therewith. v

12. A drawing and flattening table for continuously drawn sheet glass, comprising an endless belt having an upper horizontal run on which the sheet is carried, the sheet-'carrying portion of the belt consisting of a series of rollers, an endless drawing means resting on the upper edge portions of thesheet,

means for driving this means in the direction of draw and at the same speed as the sheet, means for driving the belt, and means carried by the drawing means for rotating the sheetcarrying rollers on their own axes so as to have only rolling contact with the glass sheet.

comprising 13. A drawing and flattening table for eontinuously drawn sheet glass, comprising an endless belt having an'upper horizontal run on which the sheet is carried, the sheet-carrying portion of the belt consisting of a series of rollers, an endless drawing means resting on the upper edge portions of the sheet, means for driving this means in the direction of draw and at the same speed as the sheet,

means for driving the belt, a rack carried by the drawing means, and a gear on each sheetcarrying roller meshing with the rack.

14:. A drawmg and flattening mechanism for-continuously drawn sheet glass, comprising a pair of endless chain-loops, one at either side of the horizontal run of the sheet, a plurality of sheet-carrying rollers rotatably mounted for the chains, means for moving the chains along the guides, drawing means resting upon and travelling with the edge portions of the glass sheet, and means carried by the drawing means for rotating the rollers.

1,5. A drawing and flattening mechanism for continuously drawn sheet-glass, comprisat their ends on the chains, guides i ng a pair of endless chain-loops, one at either side of the horizontal run of. the sheet, a

pluralit of sheet-carrying rollers rotatably I mounte at their ends on the chains, guida for the chains, means .for moving the chains along the guides, an endless sheet-drawing chain loop having a lowerrun above each sheet-edge, means on the chain enga 'ng the sheet edge, a gear on the end of eac roller, and a rack on the drawing-chain meshing with the gears.

' 16. In a conveying and flattening table for 2 sheet glass, an endless chain of rollers for supporting the sheet, and means for drivin 4 the chain and simultaneously cooling the ro ers.

17. a conveying and flattening table for sheet glass, an endless chain of rollers for support-ingthe sheet, and a driving sprocket meshing with the ends of the rollers.

18, In a conveying andflattening table for sheet glass, an endless chain of rollers for supporting the sheet, a driving sprocket meshing with the ends of the rollers, and means sheet glass, a pair of endless chain loops, one

for delivering a cooling fluid through the sprocket teeth to the interior of the rollers engaged thereby. I i v 19. In a conveying andflattening table for at either side of the table, a plurality of sheet carrying rollers rotatably mounted at their ends on the chains, and means for moving chains resting on the guides, and means for.

moving the chains along the guides.

21. In a conveyin and flattening table for sheet glass, a pair 0 endle$ chain loops, one

at either sideof the table, a plurality of sheetcarrying rollers rotatably mounted at their ends on the chains, means for moving each chain through a fixed orbit, and means for tatingthose rollers upon which the sheet is carried.

22. Inla conveying and flattening table for sheet glass, a pair of endless chain loops, one

at either side of the table, a plurality of sheet carrying rollers rotatably mounted at their ends on the chains, fixed guides, means on the chains resting on the guides,means for moving the chains along the guides, and means for rotating those rollers "upon which the sheet is carried.

Signed at Toledo, in the county of Lucas and-State of Ohio, this 27th day of March, 1924. I s

ENOCH T. FERNGREN. 

